Co-extruded, biaxially oriented, matte, HDPE films

ABSTRACT

Disclosed are compositions and methods for multilayer films, which, in one embodiment may comprise a core layer comprising at least 50 wt. % of high-density polyethylene. Further, the multilayer film may include a first skin layer comprising, consisting essentially of, or consisting of low-density polyethylene, optionally linear, and at least about 80 wt. % of high-density polyethylene, as well as a second skin layer comprising either: (i) one or more low-density polyethylenes, any or all of them optionally being linear; or (ii) one or more polypropylene-based copolymers. The multilayer film may be oriented in at least one direction.

REFERENCE TO RELATED APPLICATIONS

This is a continuation application, which claims priority to U.S.non-provisional patent application Ser. No. 17/219,736 filed on 31 Mar.2021 that claims priority to Patent Treaty Cooperation applicationnumber PCT/US20/38376 filed on Jun. 18, 2020 that claims priority toeach of U.S. provisional patent application Ser. No. 62/908,628 filed on1 Oct. 2019, 62/865,570 filed on 24 Jun. 2019, 62/865,558 filed on 24Jun. 2019, and 62/863,938 filed on 20 Jun. 2019, wherein each of theforegoing is hereby incorporated by this reference in its entity and isowned by Applicant.

FIELD

This application relates to multilayer films that may have orientedlayer(s), such as the core, tie, and/or skin layers, and includepolyethylene in one or more layers of the film.

BACKGROUND

This disclosure provides for new multilayer films and methods thatprovide matte films, all or some of which may be recyclable,particularly for embodiments containing all polyethylene. Additionallyand alternatively, the disclosed multilayer films and methods may haveimproved stiffness. Alongside the foregoing functional and environmentalimprovements, these new multilayer films may be use in laminating,packaging and/or labelling applications.

SUMMARY

Disclosed are compositions and methods for multilayer films, which, inone embodiment may include a core layer comprising at least about 50 wt.% of high-density polyethylene. Further, the multilayer film may includea first skin layer comprising, consisting essentially of, or consistingof low-density polyethylene, optionally linear, and at least about 80wt. % of high-density polyethylene, and a second skin layer comprising,consisting essentially of, or consisting of either: (i) one or morelow-density polyethylenes, optionally any or all of them being linear;or (ii) one or more polypropylene-based copolymers. The multilayer filmmay be oriented in at least one direction.

DETAILED DESCRIPTION

Below, directional terms, such as “above,” “below,” “upper,” “lower,”“front,” “back,” “top,” “bottom,” etc., are used for convenience inreferring to the accompanying drawings. In general, “above,” “upper,”“upward,” “top,” and similar terms refer to a direction away the earth'ssurface, and “below,” “lower,” “downward,” “bottom,” and similar termsrefer to a direction toward the earth's surface, but is meant forillustrative purposes only, and the terms are not meant to limit thedisclosure.

Various specific embodiments, versions and examples are described now,including exemplary embodiments and definitions that are adopted hereinfor purposes of understanding. While the following detailed descriptiongives specific preferred embodiments, those skilled in the art willappreciate that these embodiments are exemplary only, and that thedisclosure can be practiced in other ways. For purposes of determininginfringement, the scope of the invention will refer to the any claims,including their equivalents, and elements or limitations that areequivalent to those that are recited.

Generally, disclosed are oriented (i.e., monoaxially and/or biaxially),multilayer, polyethylene (“PE”) films that are optionally laminated toPE substrate, metallized or not, so as to create a mono-materiallaminate in some embodiments, which may, for instance, permit easyrecycling, and/or in some embodiments improve stiffness as compared toincumbent films and laminates thereof.

As used herein, “polymer” may be used to refer to homopolymers,copolymers, interpolymers, terpolymers, etc. Likewise, a “copolymer” mayrefer to a polymer comprising two monomers or to a polymer comprisingthree or more monomers.

As used herein, “intermediate” is defined as the position of one layerof a multilayered film, wherein said layer lies between two otheridentified layers. In some embodiments, the intermediate layer may be indirect contact with either or both of the two identified layers. Inother embodiments, additional layers may also be present between theintermediate layer and either or both of the two identified layers.

As used herein, “elastomer” is defined as a propylene-based orethylene-based copolymer that can be extended or stretched with force toat least 100% of its original length, and upon removal of the force,rapidly (e.g., within 5 seconds) returns to its original dimensions.

As used herein, “plastomer” is defined as a propylene-based orethylene-based copolymer having a density in the range of 0.850 g/cm³ to0.920 g/cm³ and a DSC melting point of at least 40° C.

As used herein, “substantially free” is defined to mean that thereferenced film layer is largely, but not wholly, absent a particularcomponent. In some embodiments, small amounts of the component may bepresent within the referenced layer as a result of standardmanufacturing methods, including recycling of film scraps and edge trimduring processing.

By “consist essentially of,” what is meant, for example, is that aparticular film layer does not have any more than 1 wt % or 2 wt % or 3wt % or 4 wt % or 5 wt % of other polymers in the bulk materialconstituting the film layer's composition, but “consist essentially of”does not exclude the possibility that the particular film layer also hasadditives, such as anti-slip agents, anti-blocking agents,anti-oxidants, pigments, whitening agents, cavitation agents, etc.regardless of what polymers or other materials make up the additive(s).

As used herein, “about” means the number itself and/or within 5% of thestated number. For instance, with about 5%, this means 5 and/or anynumber or range within the range of 4.75 to 5.25, e.g., 4.75 to 4.96,4.81 to 5.1, etc.

Core Layer

As is known to those skilled in the art, the core layer of amultilayered film is most commonly the thickest layer and provides thefoundation of the multilayered structure. In some embodiments, the corelayer comprises, consists essentially of, or consists of biaxiallyoriented polyethylene (“BOPE”), such as a high-density polyethylene film(“HDPE”) and/or other PE's having a density greater than 0.94 g/cm³. Invarious embodiments, the core layer comprises at least 50 wt %, at least60 wt %, at least 70 wt %, at least 80 wt %, at least 85 wt %, at least90 wt %, at least 95 wt %, or more of HDPE. In alternative embodiments,the core layer may also include other polymers, including, for instance,biaxially oriented polypropylene (“BOPP”), biaxially oriented polyester(“BOPET”), biaxially oriented polylactic acid (“BOPLA”), andcombinations thereof. In still alternate embodiments the core layer mayalso contain lesser amounts of additional polymer(s) selected from thegroup consisting of ethylene polymer, ethylene-propylene copolymers,ethylene-propylene-butene terpolymers, elastomers, plastomers, differenttypes of metallocene-LLDPEs (m-LLDPEs), and combinations thereof.

The core layer may further include a hydrocarbon resin. Hydrocarbonresins may serve to enhance or modify the flexural modulus, improveprocessability, or improve the barrier properties of the film. The resinmay be a low molecular weight hydrocarbon that is compatible with thecore polymer. Optionally, the resin may be hydrogenated. The resin mayhave a number average molecular weight less than 5000, preferably lessthan 2000, most preferably in the range of from 500 to 1000. The resincan be natural or synthetic and may have a softening point in the rangeof from 60° C. to 180° C.

Suitable hydrocarbon resins include, but are not limited to petroleumresins, terpene resins, styrene resins, and cyclopentadiene resins. Insome embodiments, the hydrocarbon resin is selected from the groupconsisting of aliphatic hydrocarbon resins, hydrogenated aliphatichydrocarbon resins, aliphatic/aromatic hydrocarbon resins, hydrogenatedaliphatic aromatic hydrocarbon resins, cycloaliphatic hydrocarbonresins, hydrogenated cycloaliphatic resins, cycloaliphatic/aromatichydrocarbon resins, hydrogenated cycloaliphatic/aromatic hydrocarbonresins, hydrogenated aromatic hydrocarbon resins, polyterpene resins,terpene-phenol resins, rosins and rosin esters, hydrogenated rosins androsin esters, and combinations thereof.

The amount of such hydrocarbon resins, either alone or in combination,in the core layer is preferably less than 20 wt %, more preferably inthe range of from 1 wt % to 5 wt %, based on the total weight of thecore layer.

The core layer may further comprise one or more additives such asopacifying agents, pigments, colorants, cavitating agents, slip agents,antioxidants, anti-fog agents, anti-static agents, fillers, moisturebarrier additives, gas barrier additives, and combinations thereof, asdiscussed in further detail below. A suitable anti-static agent isARMOSTAT™ 475 (commercially available from Akzo Nobel of Chicago, Ill.).

Cavitating agents may be present in the core layer in an amount lessthan 30 wt %, preferably less than 20 wt %, most preferably in the rangeof from 2 wt % to 10 wt %, based on the total weight of the core layer.

Preferably, the total amount of additives in the core layer comprises upto about 20 wt. % of the core layer, but some embodiments may compriseadditives in the core layer in an amount up to about 30 wt % of the corelayer.

The core layer preferably has a thickness in the range of from about 5μm to 100 μm, more preferably from about 5 μm to 50 μm, most preferablyfrom 5 μm to 25 μm.

Optional Tie Layer(s)

Tie layer(s) of a multilayered film is typically used to connect twoother layers of the multilayered film structure, e.g., a core layer anda sealant layer, and is positioned intermediate these other layers. Invarious embodiments, the films may have zero, one or two tie layers. Thetie layer(s) may have the same or a different composition as compared tothe core layer.

In some embodiments, the tie layer is in direct contact with the surfaceof the core layer. In other embodiments, another layer or layers may beintermediate the core layer and the tie layer. The tie layer maycomprise one or more polymers. In addition, the polymers may include C₂polymers, maleic-anhydride-modified polyethylene polymers, C₃ polymers,C₂C₃ random copolymers, C₂C₃C₄ random terpolymers, heterophasic randomcopolymers, C₄ homopolymers, C₄ copolymers, metallocene polymers,propylene-based or ethylene-based elastomers and/or plastomers,ethyl-methyl acrylate (EMA) polymers, ethylene-vinyl acetate (EVA)polymers, polar copolymers, and combinations thereof. For example, onepolymer may be a grade of VISTAMAXX™ polymer (commercially availablefrom ExxonMobil Chemical Company of Baytown, Tex.), such as VM6100 andVM3000 grades. Alternatively, suitable polymers may include VERSIFY™polymer (commercially available from The Dow Chemical Company ofMidland, Mich.), Basell CATALLOY™ resins such as ADFLEX™ T100F, SOFTELL™Q020F, CLYRELL™ SM1340 (commercially available from Basell Polyolefinsof The Netherlands), PB (propylene-butene-1) random copolymers, such asBasell PB 8340 (commercially available from Basell Polyolefins of TheNetherlands), Borealis BORSOFT™ SD233CF, (commercially available fromBorealis of Denmark), EXCEED™ 1012CA and 1018CA metallocenepolyethylenes, EXACT™ 5361, 4049, 5371, 8201, 4150, 3132 polyethyleneplastomers, EMCC 3022.32 low density polyethylene (LDPE) (commerciallyavailable from ExxonMobil Chemical Company of Baytown, Tex.).

In some embodiments, the tie layer may further comprise one or moreadditives such as opacifying agents, pigments, colorants, cavitatingagents, slip agents, antioxidants, anti-fog agents, anti-static agents,anti-block agents, fillers, moisture barrier additives, gas barrieradditives, and combinations thereof, as discussed in further detailbelow.

The thickness of the tie layer is typically in the range of from about0.50 to 25 μm, preferably from about 0.50 μm to 12 μm, more preferablyfrom about 0.50 μm to 6 μm, and most preferably from about 2.5 μm to 5μm. However, in some thinner films, the tie layer thickness may be fromabout 0.5 μm to 4 μm, or from about 0.5 μm to 2 μm, or from about 0.5 μmto 1.5 μm.

In various embodiments, the film, whether laminated or not, may have oneor more tie layers. In some of these embodiments, at least one of theone or more tie layers is matte. In some other embodiments, at least oneof the one or more tie layers is clear/transparent.

Skin Layer(s), Including Metallizable Skin Layers and Printable Layers

In some embodiments, the skin layer comprises at least one polymerselected from the group comprising, consisting essentially of, and/orconsisting of polyethylene copolymers or terpolymers, which may begrafted or copolymerized. In some embodiments, the polyethylene(s) maycomprise an acid-containing portion, which may be acrylic-acid based,methacrylic-acid based, another organic acid, or combinations thereof.The acid-containing portion of the acid-containing polymer may be from 4wt % through 20 wt %, or 6 wt % through 16 wt %, or 8 wt % through 12 wt%. As examples, Exxon Mobil Escor EAA resins or Dupont Nucrel EAA resinsor Dow Primacor EAA resins might be used. For metallizing or barrierproperties, the acid-modified skin layer may contain LLDPE or ethylenevinyl alcohol based polymer(s) (“EVOH”), a suitable EVOH copolymer isEVAL™ G176B or XEP 1300 (commercially available from Kuraray CompanyLtd. of Japan).

The skin layer may also comprise processing aid additives, such asanti-block agents, anti-static agents, slip agents and combinationsthereof, as discussed in further detail below.

The thickness of the skin layer depends upon the intended function ofthe skin layer, but is typically in the range of from about 0.20 μmthrough 3.5 μm, or from 0.30 μm through 2 μm, or in many embodiments,from 0.50 μm through 1.0 μm. In thin film embodiments, the skin layerthickness may range from about 0.20 μm through 1.5 μm, or 0.50 μmthrough 1.0 μm.

Additives

Additives present in the film's layer(s) may include, but are notlimited to opacifying agents, pigments, colorants, cavitating agents,slip agents, antioxidants, anti-fog agents, anti-static agents,anti-block agents, fillers, moisture barrier additives, gas barrieradditives, gas scavengers, and combinations thereof. Such additives maybe used in effective amounts, which vary depending upon the propertyrequired, and may be added to one or more of the film's layer(s) insolid or solution form, e.g., part of a masterbatch solution orotherwise.

Examples of suitable opacifying agents, pigments or colorants are ironoxide, carbon black, aluminum, titanium dioxide (TiO₂), calciumcarbonate (CaCO₃), and combinations thereof.

Cavitating or void-initiating additives may include any suitable organicor inorganic material that is incompatible with the polymer material(s)of the layer(s) to which it is added, at the temperature of biaxialorientation, in order to create an opaque film. Examples of suitablevoid-initiating particles are PBT, nylon, solid or hollow pre-formedglass spheres, metal beads or spheres, ceramic spheres, calciumcarbonate, talc, chalk, or combinations thereof. The average diameter ofthe void-initiating particles typically may be from about 0.1 to 10 μm.

Slip agents may include higher aliphatic acid amides, higher aliphaticacid esters, waxes, silicone oils, and metal soaps. Such slip agents maybe used in amounts ranging from 0.1 wt % to 2 wt % based on the totalweight of the layer to which it is added. An example of a slip additivethat may be useful is erucamide.

Non-migratory slip agents, used in one or more skin layers of themultilayered films, may include polymethyl methacrylate (PMMA). Thenon-migratory slip agent may have a mean particle size in the range offrom about 0.5 μm to 8 μm, or 1 μm to 5 μm, or 2 μm to 4 μm, dependingupon layer thickness and desired slip properties. Alternatively, thesize of the particles in the non-migratory slip agent, such as PMMA, maybe greater than 20% of the thickness of the skin layer containing theslip agent, or greater than 40% of the thickness of the skin layer, orgreater than 50% of the thickness of the skin layer. The size of theparticles of such non-migratory slip agent may also be at least 10%greater than the thickness of the skin layer, or at least 20% greaterthan the thickness of the skin layer, or at least 40% greater than thethickness of the skin layer. Generally spherical, particulatenon-migratory slip agents are contemplated, including PMMA resins, suchas EPOSTAR™ (commercially available from Nippon Shokubai Co., Ltd. ofJapan). Other commercial sources of suitable materials are also known toexist. Non-migratory means that these particulates do not generallychange location throughout the layers of the film in the manner of themigratory slip agents. A conventional polydialkyl siloxane, such assilicone oil or gum additive having a viscosity of 10,000 to 2,000,000centistokes is also contemplated.

Suitable anti-oxidants may include phenolic anti-oxidants, such asIRGANOX® 1010 (commercially available from Ciba-Geigy Company ofSwitzerland). Such an anti-oxidant is generally used in amounts rangingfrom 0.1 wt % to 2 wt %, based on the total weight of the layer(s) towhich it is added.

Anti-static agents may include alkali metal sulfonates,polyether-modified polydiorganosiloxanes, polyalkylphenylsiloxanes, andtertiary amines. Such anti-static agents may be used in amounts rangingfrom about 0.05 wt % to 3 wt %, based upon the total weight of thelayer(s).

Examples of suitable anti-blocking agents may include silica-basedproducts such as SYLOBLOC® 44 (commercially available from Grace DavisonProducts of Colombia, Md.), PMMA particles such as EPOSTAR™(commercially available from Nippon Shokubai Co., Ltd. of Japan), orpolysiloxanes such as TOSPEARL™ (commercially available from GE BayerSilicones of Wilton, Conn.). Such an anti-blocking agent comprises aneffective amount up to about 3000 ppm of the weight of the layer(s) towhich it is added.

Useful fillers may include finely divided inorganic solid materials suchas silica, fumed silica, diatomaceous earth, calcium carbonate, calciumsilicate, aluminum silicate, kaolin, talc, bentonite, clay and pulp.

Optionally, nonionic or anionic wax emulsions can be included in thecoating(s), i.e., skin layer(s), to improve blocking resistance and/orlower the coefficient of friction. For example, an emulsion of MichemLube 215, Michem Lube 160 may be included in the skin layer(s). Anyconventional wax, such as, but not limited to Carnauba™ wax(commercially available from Michelman Corporation of Cincinnati, Ohio)that is useful in thermoplastic films is contemplated.

Metallization

The outer surface (i.e., side facing away from the core) of a skin layerand/or laminating substrate may undergo metallization after optionallybeing treated. Metallization may be carried out through conventionalmethods, such as vacuum metallization by deposition of a metal layersuch as aluminum, copper, silver, chromium, or mixtures thereof.Following metallization, a coating may be applied to the outermetallized layer “outside” or “inside” the vacuum chamber to result inthe following structure: metallized layer/skin layer/optional tielayer/core/optional tie layer/skin layer/metallized layer. In anadditional embodiment, a primer may be applied on the metal surface(s)followed by top coating(s).

In certain embodiments, the metal for metallization is metal oxide, anyother inorganic materials, or organically modified inorganic materials,which are capable of being vacuum deposited, electroplated or sputtered,such as, for example, SiOx, AlOx, SnOx, ZnOx, IrOx, wherein x=1 or 2,organically modified ceramics “ormocer”, etc. The thickness of thedeposited layer(s) is typically in the range from 100 to 5,000 Angstromor preferably from 300 to 3000 Angstrom.

Surface Treatment

One or both of the outer surfaces of the multilayered films may besurface-treated to increase the surface energy to render the filmreceptive to metallization, coatings, printing inks, adhesives, and/orlamination. The surface treatment can be carried out according to one ofthe methods known in the art including corona discharge, flame, plasma,chemical treatment, or treatment by means of a polarized flame.

Priming

An intermediate primer coating may be applied to multilayered films. Inthis case, the film may be first treated by one of the foregoing methodsto provide increased active adhesive sites thereon and to thethus-treated film surface there may be subsequently applied a continuouscoating of a primer material. Such primer materials are well known inthe art and include, for example, epoxy, poly(ethylene imine) (PEI), andpolyurethane materials. U.S. Pat. Nos. 3,753,769, 4,058,645 and4,439,493, each incorporated herein by reference, discloses the use andapplication of such primers. The primer provides an overall adhesivelyactive surface for thorough and secure bonding with the subsequentlyapplied coating composition and can be applied to the film byconventional solution coating means, for example, by roller application.

Orienting

The films herein are also characterized in certain embodiments as beingbiaxially oriented. The films can be made by any suitable techniqueknown in the art, such as a tentered or blown process, LISIM™, andothers. Further, the working conditions, temperature settings, linesspeeds, etc. will vary depending on the type and the size of theequipment used. Nonetheless, described generally here is one method ofmaking the films described throughout this specification. In aparticular embodiment, the films are formed and biaxially oriented usingthe tentered method. In the tentered process, line speeds of greaterthan 100 m/min to 400 m/min or more, and outputs of greater than 2000kg/h to 4000 kg/h or more are achievable. In the tenter process,sheets/films of the various materials are melt blended and coextruded,such as through a 3, 4, 5, 7-layer die head, into the desired filmstructure. Extruders ranging in diameters from 100 mm to 300 or 400 mm,and length to diameter ratios ranging from 10/1 to 50/1 can be used tomelt blend the molten layer materials, the melt streams then metered tothe die having a die gap(s) within the range of from 0.5 or 1 to anupper limit of 3 or 4 or 5 or 6 mm. The extruded film is then cooledusing air, water, or both. Typically, a single, large diameter rollpartially submerged in a water bath, or two large chill rolls set at 20or 30 to 40 or 50 or 60 or 70° C. are suitable cooling means. As thefilm is extruded, an air knife and edge pinning are used to provideintimate contact between the melt and chill roll.

Downstream of the first cooling step in this embodiment of the tenteredprocess, the unoriented film is reheated to a temperature of from 80 to100 or 120 or 150° C., in one embodiment by any suitable means such asheated S-wrap rolls, and then passed between closely spaced differentialspeed rolls to achieve machine direction orientation. It is understoodby those skilled in the art that this temperature range can varydepending upon the equipment, and in particular, upon the identity andcomposition of the components making up the film. Ideally, thetemperature will be below that which will melt the film, but high enoughto facilitate the machine direction orientation process. Suchtemperatures referred to herein refer to the film temperature itself.The film temperature can be measured by using, for example, infraredspectroscopy, the source aimed at the film as it is being processed;those skilled in the art will understand that for transparent films,measuring the actual film temperature will not be as precise. Theheating means for the film line may be set at any appropriate level ofheating, depending upon the instrument, to achieve the stated filmtemperatures.

The lengthened and thinned film is passed to the tenter section of theline for TD orientation. At this point, the edges of the sheet aregrasped by mechanical clips on continuous chains and pulled into a long,precisely controlled hot air oven for a pre-heating step. The filmtemperatures range from 100 or 110 to 150 or 170 or 180° C. in thepre-heating step. Again, the temperature will be below that which willmelt the film, but high enough to facilitate the step of transversedirection orientation. Next, the edges of the sheet are grasped bymechanical clips on continuous chains and pulled into a long, preciselycontrolled hot air oven for transverse stretching. As the tenter chainsdiverge a desired amount to stretch the film in the transversedirection, the process temperature is lowered by at least 2° C. buttypically no more than 20° C. relative to the pre-heat temperature tomaintain the film temperature so that it will not melt the film. Afterstretching to achieve transverse orientation in the film, the film isannealed at a temperature below the melting point, and the film is thencooled from 5 to 10 or 15 or 20 or 30 or 40° C. below the stretchingtemperature, and the clips are released prior to edge trim, optionalcoronal, printing and/or other treatment can then take place, followedby winding.

Thus, TD orientation is achieved by the steps of pre-heating the filmhaving been machine oriented, followed by stretching and annealing it ata temperature below the melt point of the film, and then followed by acooling step at yet a lower temperature. In one embodiment, the filmsdescribed herein are formed by imparting a transverse orientation by aprocess of first pre-heating the film, followed by a decrease in thetemperature of the process within the range of from 2 or 3 to 5 to 10 or15 or 20° C. relative to the pre-heating temperature while performingtransverse orientation of the film, followed by a lowering of thetemperature within the range of from 5° C. to 10 or 15 or 20 or 30 or40° C. relative to the melt point temperature, holding or slightlydecreasing (more than 5%) the amount of stretch, to allow the film toanneal. The latter step imparts the low TD shrink characteristics of thefilms described herein. Thus, for example, where the pre-heattemperature is 120° C., the stretch temperature may be 114° C., and thecooling step may be 98° C., or any temperature within the rangesdisclosed. The steps are carried out for a sufficient time to affect thedesired film properties as those skilled in the art will understand.

Thus, in certain embodiments the film(s) described herein are biaxiallyoriented with at least a 5 or 6 or 7 or 8-fold TD orientation and atleast a 2 or 3 or 4-fold MD orientation. Being so formed, the at leastthree-layer (one core, two skin layers, 18-21 μm thickness) possess anultimate tensile strength within the range of from 100 or 110 to 80 or90 or 200 MPa in the TD in certain embodiments; and possess an ultimatetensile strength within the range of from 30 or 40 to 150 or 130 MPa inthe MD in other embodiments. Further, the SCS films described hereinpossess an MD Elmendorf tear is greater than 10 or 15 g in certainembodiments, and the 25 TD Elmendorf tear is greater than 15 or 20 g inother embodiments.

INDUSTRIAL APPLICABILITY

The disclosed multilayered films may be stand-alone films, laminates, orwebs. Or, the multilayered films may be sealed, coated, metallized,and/or laminated to other film structures. The laminating substrate,itself, may for instance, be a BOPE or a non-oriented, cast or blown PEfilm with or without the assistance of adhesive(s), increases intemperature and/or pressure, water or solvents, etc.; furthermore, thelaminating substrate may or may not be metallized and/or coated. Thedisclosed multilayered films may be prepared by any suitable methodscomprising the steps of co-extruding a multilayered film according tothe description and claims of this specification, orienting andpreparing the film for intended use such as by coating, printing,slitting, or other converting methods.

For some applications, it may be desirable to laminate the multilayeredfilms to other polymeric film or paper products for purposes such aspackage decor including printing and metallizing. These activities aretypically performed by the ultimate end-users or film converters whoprocess films for supply to the ultimate end-users.

The prepared multilayered film may be used as a flexible packaging filmto package an article or good, such as a food item or other product. Insome applications, the film may be formed into a pouch type of package,such as may be useful for packaging a beverage, liquid, granular, ordry-powder product.

EXAMPLE EMBODIMENTS

The following are example, recyclable films in line with the foregoingdisclosure, wherein these examples may be modified in line with theforegoing disclosure in other example embodiments:

Example 1

optionally treated L1 skin about ≥50 wt. % HDPE-modified matte layer and0.5-2 ≤20 wt. % (L)LDPE, and, optionally, ≤ wt. % μm of the (L)LDPE inHCR, PE polymers, waxes, COCs, or any combination of HCR, PE polymers,waxes, COCs so as to promote stretching of this layer L3 core about HDPE(and optionally ≤20 wt. % LLDPE) 10 to 50 μm L5 skin about mLLDPE,LLDPE, LDPE or combinations thereof 0.5-2 μm optionally treatedoptionally primed, coated, and/or metallized

Example 2

optionally treated L1 skin about ≥50 wt. % HDPE-modified matte layer and0.5-2 ≤20 wt. % (L)LDPE, and, optionally, ≤ wt. % μm of the (L)LDPE inHCR, PE polymers, waxes, COCs, or any combination of HCR, PE polymers,waxes, COCs so as to promote stretching of this layer L2 tie about 1-HDPE 5 μm L3 core about HDPE (and optionally ≤20 wt. % LLDPE) 10-50 μmL4 tie about 1-5 HDPE + LLDPE + OBC (i.e., olefin block μm copolymer) L6skin about 1 PP-based copolymer(s) and/or terpolymer(s) μm optionallytreated optionally primed, coated, and/or metallized

In Example 2, in various embodiments, L4's composition contains at least40 wt. % HDPE, and more preferably, at least 50 wt. %, and still morepreferably, at least 60 wt. % in combination with from 10 wt. % through40 wt. % of each of the LLDPE (or LDPE in some embodiments) and OBC inorder to help bind the polypropylene-based polymer(s) in L6 to the HDPEin L3; L2 does not need such binding assistance.

Additives, such as hydrocarbon resins, waxes and/or cyclic olefincopolymers (“COCs”), in the skin layer may modify the HDPE in order tomake the skin layer stretchable without fracturing. In one exampleembodiment, additives may be melted at the stretching temperature, havelow viscosity and lubricate the HDPE molecules to help stretch the skinlayer. Examples of HCR's include, but are not limited to aliphatichydrocarbon resins, aromatic modified aliphatic hydrocarbon resins,aliphatic/aromatic resins, polycyclic resins, hydrogenated polycyclicresins, hydrogenated polycyclic aromatic resins, hydrogenated aromaticresins in which a substantial portion of the benzene rings are convertedto cyclohexane rings, gum rosins, gum rosin esters, wood rosins, woodrosin esters, tall oil rosins, tall oil rosin esters, polyterpenes,aromatic modified polyterpenes, terpene phenolics, and combinationsthereof. Also in example embodiments, L3 may be cavitated, such as withPBT, nylon, solid or hollow pre-formed glass spheres, metal beads orspheres, ceramic spheres, calcium carbonate, talc, chalk, orcombinations thereof. In yet more example embodiments, any or all layersmay contain slip-migrating additives, antistatic agents or combinationsthereof, and L1, L5, and L6 may also antiblock agents.

In addition to the example embodiments shown at Examples 1 and 2,variations from these embodiments exist in keeping with the disclosure.For example, thicknesses of the layers may range as follows: L1, L5 andL6=0.5 to 2 μm; L2, L4=1 to 5 μm; L3=10 to 50 μm. And, L1 may include≥50 wt. % HDPE, e.g., 50 wt. %, 55 wt. %, 60 wt. %, 65 wt. %, 70 wt. %,75 wt. %, 80 wt. %, 85 wt. %, or 90 wt. % (or any range therebetween anyof the foregoing wt. %'s) in combination with ≤20 wt. % (L)LDPE (i.e.“(L)” means optionally linear) only outside of optionally includingadditives as disclosed herein, and/or optionally, ≤wt. % of the (L)LDPEin HCR, PE polymers, waxes, COCs, or any combination of HCR, PEpolymers, waxes, COCs. That is, the ≤wt. % of the (L)LDPE is the same orgreater than any one or any combination of HCR, PE polymers, waxes,and/or COCs that may be present in L1, optionally including additives asdisclosed herein, e.g., ≤5 wt. % additives in L1 or any layer for thatmatter. The variations presented in this paragraph beneficially producethe same qualitative results in Examples 5 and 6 below as compared toExamples 1-4, i.e., higher haze, generally about the same or lower gloss(except for Example 4), and lower than 1 coefficients of friction.

Turning to the components, below are some tradenames and/or propertiesof resins that may be used in the disclosed films:

ExxonMobil HTA108: HDPE, MI 190° C./2.16 kg, 0.6 g/10 min, density0.961;

Nova Sclair 19A: HDPE, MI 190° C./2.16 kg, 0.72 g/10 min, density 0.962;

LyondelBasell Alathon M6030: HDPE, MI 190° C./2.16 kg, 3.0 g/10 min,density 0.960;

LyondellBasell Adsyl 5C39F: ethylene propylene butylene terpolymer, MI5.5 g/10 min, melting peak 132° C.;

mLLDPE: mLLDPE, MI 1.9, melting peak 127° C.;

Borealis Borstar FX1002: LLDPE, MI 190° C./5 kg, 2.0 g/10 min, density0.937; and

wherein the LLDPE may be metallocene- or ZN-catalyzed or otherwiseformed.

Haze (ASTM D1003), gloss (ASTM D2457 at 45°), and coefficients offriction (ASTM D1894) of the films are affected by the resins. Forexample, Table 1 reports on the measured haze, gloss, and coefficient offriction of the films presented in Example 1, a three-layered filmhaving an L1/L3/L5 structure as shown above, wherein the reported valueson haze and gloss have about a 10% variance.

TABLE 1 Haze Gloss Layer L1 Resin (%) (%) CoF Notes Example 1 100%LyondellBasell 5 75 >1 non-matte Adsyl 5C39F Example 2 mLLDPE 10 30 >1non-matte Example 3 100% Borealis 27 30 >1 non-matte Bor star FX1002Example 4 100% ExxonMobil 56 10 >1 matte film; HTA108 layer notuniformly stretched Example 5 LyondelBasell 35 33 0.2 matte film;Alathon M6030 + uniformly 20% LLDPE (Dow stretched Innate TF80)

It is noted that other embodiments that differ from Example 1 by havingdifferent amounts of LLDPE, HCR, and/or OBC in their films' overallcompositions result in negligible impact on the measured haze and glossvalues. As a result, the above-reported values for haze and gloss alsoapply to such other embodiments.

Turning now to five-layered films, Table 2 reports on the measured hazeand gloss of the film presented in Example 2.

TABLE 2 Haze Gloss Layer L1 Resin (%) (%) CoF Notes Example 5LyondelBasell 45 21 0.3 matte film; Alathon M6030 + uniformly 20% LLDPE(Dow stretched Innate TF80)

The disclosed films may be reverse printed with a dull appearance, aswell as laminated to a polyethylene-based sealant film to produce amono-material laminate, which can be used to produce bags forfood-packaging applications that has the additional advantage of stillbeing recyclable. Given that at least one exemplary skin is matte, thisresults in an antiblocking surface, which obviates or mitigates a needto add an antiblocking agent, such as one in a polypropylene-basedmasterbatch. However, an antiblocking agent remains an optionalcomponent to skin(s), and if so, then preferably within apolyethylene-based mixture so that the film, whether laminated or not,remains recyclable.

Below are further example embodiments of the disclosed film that arewritten in claim form:

-   1. A multilayer film comprising:    -   a core layer comprising at least about 50 wt. % of high-density        polyethylene;    -   a first skin layer comprising low-density polyethylene and at        least about 80 wt. % of high-density polyethylene; and    -   a second skin layer comprising either: (i) one or more        low-density polyethylenes; or (ii) one or more        polypropylene-based copolymers,    -   wherein the multilayer film is oriented in at least one        direction.-   2. The multilayer film of claim 1, further comprising one or more    additives.-   3. The multilayer film of claim 1, further comprising one or more    tie layers.-   4. The multilayer film of claim 3, wherein at least one layer in the    multilayer film is matte.-   5. The multilayer film of claim 3, wherein at least one of the one    or more tie layers comprise at least one olefin block copolymer.-   6. The multilayer film of claim 3, wherein at least one of the one    or more tie layers comprise at least one low-density polyethylene.-   7. The multilayer film of claim 3, wherein the one or more tie    layers comprise high-density polyethylene.-   8. The multilayer film of claim 3, wherein the one or more tie    layers comprise at least about 40 wt. % high-density polyethylene.-   9. The multilayer film of claim 1, wherein the core layer further    comprises about 20 wt. % or less of linear, low-density    polyethylene.-   10. The multilayer film of claim 1, wherein the first skin layer    further comprises hydrocarbon resin.-   11. The multilayer film of claim 1, wherein the first skin layer    further comprises wax.-   12. The multilayer film of claim 1, wherein the first skin layer    further comprises hydrocarbon resin, cyclic olefin copolymer,    polyethylene polymer (e.g. homo-, co-, and/or terpolymers), wax, or    combination thereof, and optionally in a combined amount having a    lower wt. % than a wt. % present for the low-density polyethylene,    which is optionally linear.-   13. The multilayer film of claim 1, wherein at least one of the one    or more low-density polyethylenes and/or the low-density    polyethylene is metallocene-catalyzed.-   14. The multilayer film of claim 1, wherein at least one of the one    or more low-density polyethylenes and/or the low-density    polyethylene is linear.-   15. The multilayer film of claim 1, wherein the multilayer film is    metallized.-   16. The multilayer film of claim 1, wherein the multilayer film is    coated.-   17. The multilayer film of claim 1, wherein the first skin layer is    laminated to a polyethylene film.-   18. The multilayer film of claim 1, wherein the first skin layer    further comprises an antiblock agent, optionally within a    masterbatch solution.-   19. The multilayer film of claim 1, wherein haze of the multilayer    film is at least about 70% and gloss is at or below about 25%.-   20. The multilayer film of claim 1, wherein at least two layers of    the multilayer film are coextruded, and, in alternate embodiments,    more than two layers are coextruded, and, in still alternate    embodiments at least all skin, tie and core layers are coextruded.-   21. The multilayer film of claim 1, wherein the film is treated.

While the foregoing is directed to example embodiments of the disclosedinvention, other and further embodiments may be devised withoutdeparting from the basic scope thereof, wherein the scope of thedisclosed compositions, systems and methods are determined by one ormore claims.

What is claimed is:
 1. A multilayer film comprising: a core layercomprising at least about 50 wt. % of high-density polyethylene; a firstskin layer comprising of low-density polyethylene and at least about 80wt. % of high-density polyethylene; and a second skin layer comprisingeither: (i) one or more low-density polyethylenes; or (ii) one or morepolypropylene-based copolymers, wherein the multilayer film is biaxiallyoriented.
 2. The multilayer film of claim 1, further comprising one ormore additives.
 3. The multilayer film of claim 1, further comprisingone or more tie layers.
 4. The multilayer film of claim 3, wherein atleast one layer in the multilayer film is matte.
 5. The multilayer filmof claim 3, wherein at least one of the one or more tie layers compriseat least one olefin block copolymer.
 6. The multilayer film of claim 3,wherein at least one of the one or more tie layers comprise at least onelow-density polyethylene.
 7. The multilayer film of claim 3, wherein theone or more tie layers comprise high-density polyethylene.
 8. Themultilayer film of claim 3, wherein the one or more tie layers compriseat least about 40 wt. % high-density polyethylene.
 9. The multilayerfilm of claim 1, wherein the core layer further comprises about 20 wt. %or less of linear, low-density polyethylene.
 10. The multilayer film ofclaim 1, wherein the first skin layer further comprises hydrocarbonresin.
 11. The multilayer film of claim 1, wherein the first skin layerfurther comprises wax.
 12. The multilayer film of claim 1, wherein thefirst skin layer further comprises hydrocarbon resin, polyethylenepolymer, cyclic olefin copolymer, wax or combination thereof.
 13. Themultilayer film of claim 1, wherein at least one of the one or morelow-density polyethylenes and/or the low-density polyethylene ismetallocene-catalyzed.
 14. The multilayer film of claim 1, wherein atleast one of the one or more low-density polyethylenes and/or thelow-density polyethylene is linear.
 15. The multilayer film of claim 1,wherein the multilayer film is treated.
 16. The multilayer film of claim1, wherein the multilayer film is metallized.
 17. The multilayer film ofclaim 1, wherein the multilayer film is coated.
 18. The multilayer filmof claim 1, wherein the first skin layer is laminated to a polyethylenefilm.
 19. The multilayer film of claim 1, wherein the first skin layerfurther comprises an antiblock agent, optionally within a masterbatchsolution.
 20. The multilayer film of claim 1, wherein at least twolayers of the multilayer film are coextruded.